A. logc=(m2−n)loga−mnnloga−m
B. logc=(n2−m)loga−mnnloga−m
C. logc=(n2−m)loga−nnloga−mn
D. logc=(m2−n)loga−mnmloga−n
Chọn B.
a=10mn−logb⇔loga=mn−logb⇔n−logb=mloga⇔logb=nloga−mloga;
b=10mn−logc⇔logb=mn−logc
Ta có
logb=mn−logc=nloga−mloga⇔n−logc=mloganloga−m⇔logc=(n2−m)loga−mnnloga−m